Polyetherurethanes (PEU's) demonstrate great potential for use in artificial heart and other blood contact applications. Recently our research group has observed a relationship between the surface chemistry of PEU's as measured by ESCA and their blood compatibility. However, this information cannot be used to design more blood compatible PEU's since the relationship between bulk and surface properties for this class of materials has not been established. In this proposal methods are described for establishing this relationship. A variety of PEU's and low molecular weight model compounds will be synthesized. These materials will be studied by ESCA, ATR-IR, contact angle measurement, SEM, TEM, and DSC. The following factors and their effect on surface structure will be considered: polymer composition, casting surface composition, casting solvent, thermal history, surface stability, and extraction. ESCA techniques for analysis will be emphasized. ESCA will be used to provide a general, quantitative description of the surface which can be related to parameters such as critical surface tension and also to explore the domain structure of these polymers. Unique aspects of this proposal are the study of the thermal stability of oriented PEU surfaces, methods for "fine-tuning" cast PEU surface composition, the preparation of sequentially grafted, homogeneous PEU's and the development of a general expression to describe polymer surfaces.